Connect to DB in snippet

/* Table names to process this is only necessary if your table prefix is
 * the same as that of the MODx tables. You can send a comma-separated list
 * of full table names. In that case the class name will be the table name 
 * minus the prefix with any underscores removed and any letter after an 
 * underscore in upper case.
 *
 * You can also send an array of arrays of tableName => className, 
 * which allows you to specify the exact class name rather then letting
 * MODx create it from the table name. Each inner array specifies a full
 * table name and the class name to use.
 *
 * NOTE: This feature may not be implemented yet.
 *
 * Examples:
 *
 *$myTables = 'bobs_quotation';
 *
 *$myTables = array(
 *   array(
 *     'bobs_quotation'=>'bobQuotation'
 *  )
 *);
 *
*/

$loginemail = $_POST['loginemail'] ;
$loginpassword = $_POST['loginpassword'] ;

$logincheck = "SELECT * FROM `ft_gameusers` WHERE `email` = '".$loginemail."' AND `password` = '".$loginpassword."'";

$query = $modx->query($logincheck);

if ($query) {
    while ($row = $query->fetch(PDO::FETCH_ASSOC)) {

 echo $row['email'];

    }
}

 You can also send an array of arrays of tableName => className,